A variety of different sealing mechanisms are used to prevent the backflow of blood or other fluids from a patient during certain types of treatment or diagnostic procedures. In a typical transluminal treatment or diagnostic scenario, a clinician controls such a mechanism to alternately block or open a fluid conduit extending from outside the patient into an intraluminal space such as a vein or artery. Transluminal devices such as wire guides and catheters may be passed through the conduit when open, and backflow of blood or another fluid can be prevented when the conduit is closed. Since it is often necessary for transluminal devices to reside within the fluid conduit when a seal is established, many sealing mechanisms are engineered to fluidly seal around a wire guide, catheter or the like.
One particular strategy employs a push/pull sleeve or tube, coupled with a housing, which can be advanced through the center of a resilient gasket or the like positioned in the housing to open the gasket and provide a passage for introducing a transluminal device into the patient. When the push/pull sleeve is retracted, a fluid seal is formed about the device by way of a tendency for the gasket to return to a closed state. Other techniques employ a rotating mechanism which adjusts a different type of gasket from an open configuration to a closed configuration, sealing about a transluminal device. Each of these strategies has various drawbacks. In the case of rotating mechanism devices, their use can be unwieldy and slow. In certain instances, a clinician may need to seal and unseal about a device multiple times during a procedure, and the need to rotate a sealing mechanism to seal, unseal, seal again, etc. can be tiresome. In the case of push/pull devices, some of these shortcomings do not exist, as forming or un-forming a seal is fairly quick and easy. A tradeoff may exist, however, in the robustness of the seal, for at least certain of such designs. In other words, while push/pull designs may be efficient to use, the seal may not be as effective against preventing backflow of fluid from a patient.
Another known strategy is set forth in United States Patent Application Publication Number 2004/0172008 to Layer. Layer proposes a hemostasis valve having a collapsible member positionable within a valve body, and a pressure application system configured to increase a pressure within an elongate chamber in the valve body to seal the collapsible member about a medical instrument. While Layer may be suitable for its intended purposes, the strategy has various shortcomings.